The proposed longitudinal research project is part of a long-term effort by the National Institute of Dental Research to improve modalities for prevention, early detection, and treatment of oral cancers. The goal of the present research is to identify particular molecular markers for pre-malignant or malignant lesions in the oral cavity. The actual usefulness of such markers to predict development of oral malignancies will be studied in a subsequent investigation. This contract will provide data collection support services for this project.